

package com.enterprise.hadoop;
	
import java.io.IOException;
import java.util.Iterator;
import java.util.StringTokenizer;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.FileOutputFormat;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapReduceBase;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.TextInputFormat;
import org.apache.hadoop.mapred.TextOutputFormat;

public class WordCount {
	
public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, Text, IntWritable> {
	private final static IntWritable one = new IntWritable(1);
	private Text word = new Text();

	public void map(LongWritable key, Text value, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
		String line = value.toString();
		StringTokenizer tokenizer = new StringTokenizer(line);
		System.out.println("I am Mapper of line: "+ line);
		while (tokenizer.hasMoreTokens()) {
			word.set(tokenizer.nextToken());
			output.collect(word, one);
		}
	}
}

public static class Reduce extends MapReduceBase implements Reducer<Text, IntWritable, Text, IntWritable> {
	
	public void reduce(Text key, Iterator<IntWritable> values, OutputCollector<Text, IntWritable> output, Reporter reporter) throws IOException {
	    int sum = 0;
	    while (values.hasNext()) {
          sum += values.next().get();
        }
	    output.collect(key, new IntWritable(sum));
	}
}
	
	public static void main(String[] args) throws Exception {
		JobConf conf = new JobConf(WordCount.class);
	    conf.setJobName("wordcount");
		conf.setOutputKeyClass(Text.class);
		conf.setOutputValueClass(IntWritable.class);
		conf.setMapperClass(Map.class);
	    conf.setCombinerClass(Reduce.class);
	    conf.setReducerClass(Reduce.class);
		conf.setInputFormat(TextInputFormat.class);
		conf.setOutputFormat(TextOutputFormat.class);
		FileInputFormat.setInputPaths(conf, new Path(args[0]));
	    FileOutputFormat.setOutputPath(conf, new Path(args[1]));
		JobClient.runJob(conf);
    }
}
	